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Full text of "Treatise On Applied Analytical Chemistry(Vol-1)"

CASTOR OIL

Morocco and India, have a higher number (85-88). With some Moroccan oils
a number of 90 or more is obtained, but such cases are exceptional and some-
times relate to oils not of the olive but of the fruits of the Moroccan olive
(Arganum sideroxylon], a tree of that region very similar to the olive.1

Elaidin test:  should give a colourless or yellowish solid mass.

Fatty acid test, according to Tortelli and Fortini:  negative result.

Colour reactions : none should be given, either with the general reagents
for seed oils or with the special reagents for cottonseed, sesame and marine
animal oils.

In general, an olive oil may be regarded as pure when : it is coloured only
pale yellow by Heydenreich's, Hauchecorne's or Brulle's reagent, has a saponi-
fication number not less than 192 and an iodine number not exceeding 83, and
does not contain arachidic, lignoceric or erucic acid. An oil with a saponifi-
cation number less than 192 and an iodine number above 83—within, however,
the limits indicated in Table XLIV—but of normal behaviour as regards all
the other tests, may be regarded as genuine.

The official Italian methods give for olive oil the limits indicated above
for the different characters, excepting that the solidifying temperature is given
as 2-6°, the refractometer reading at 25° as between 62 and 62-8, and the iodine
number as 79-90. They give further : Reichert-Meissl number, o -3 ; Hehner
number, 95-5-96-2 ; acetyl number, 4-10 ; absolute iodine mimber, 95-104 ;
unsaponifiable residue, which should be constituted of minimum traces of
phytosterol scarcely sufficient for the reaction with chloroform and sulphuric
acid (100 grams of the oil yield 0-45-0-47 gram of crude phytosterol, whilst
sesame and cottonseed oils give respectively 1-28 and 1-20 gram).

The industrial oil for lighting or lubrication should answer the requirements
indicated for the genuine comestible oil. In some cases, however, admixtures
of seed oils (arachis, colza or ravison) are allowed, e.g., by the Italian State
Railways. It should not contain more than i% of free acid (expressed as
monohydrated sulphuric acid), should not congeal above — 5°, should not be
adulterated with animal, mineral or resin oils, and should not contain muci-
laginous substances or suspended foreign matters. Further, that for illumi-
nating purposes should satisfy definite requirements with regard to the mode
of burning, the illuminating power, etc.

Industrial olive oil for soap-making occurs in various qualities :

Washed oil, obtained by washing the olive residues (sanse) : moisture and
impurities up to 2% ; free from sulphur; acidity variable (10-40% as oleic
acid).

Huile lampante (yellow and green), obtained by filtering the washed oil:
moisture and impurities up to i%.

Olive oil grease or residues from the filtration of the washed oil: should be
free from sulphur, unbleached and not treated with acid. Its value depends
on its content in total fatty matter—to be determined directly—or on its content
in fatty acids (exclusive of hydroxy-acids)—to be determined by saponifying
the grease and separating the total fatty acids.

Sulphur or sulphocarbon olive oil, which is distinguished from sanse oil:
saponification number not less than 180, acidity (as oleic acid) up to 65%,
moisture and impurities up to 2% and hydroxy-acids up to 3%.

CASTOR   OIL

From the seeds of Ricinus commums, is almost colourless or yellowish,
dense and viscous, with characteristic smell and taste. It dissolves in
alcohol in all proportions and in acetic acid in the cold. It is, however,
almost insoluble in petroleum ether and in vaseline oil, whilst other oils are

1 Zeitschr. Unt. Nahr. Genussmittel, 1910, II, p. 749.	7-76